As the name indicates, SLIM-BOT, is a small, simple, compact robot, which may be moved or controlled using various inputs, without using any micro-controller. There is no need of programming language or coding to make and control the Slim-Bot. This is the basic project for those, who don’t have any knowledge in micro-controllers and programming. The various controls for the Slim-Bot is completely based on the electronic circuits only.
Now, the Slim-Bot may be controlled wirelessly, using HAND GESTURES using simple Hand Gesture Sensor. A Hand Gesture Sensor has a small ball in a square box, which generates four signals (Forward-Backward-Left-Right), by tilting towards its four corners. The Stop signal is generated when the ball is in idle condition, i.e., at middle position of the square box. All the outputs of Hand Gesture Sensor are digital. So, the control circuit becomes handy, easier and simpler. Here, the digital values are directly fed to Encoder IC (HT12E) and then transmitted wirelessly using RF transmitter.
The serial data, which is received by the RF receiver, sends to the Decoder IC (HT12D). The Decoder IC, decodes the received serial data, back in to 4 bit data. The 4 bit data is used to control the movement of the Slim-Bot.
About Hand Gesture Sensor:
The Hand Gesture Sensor used here is simple and easy Make-at-Home sensor. Base of the Hand Gesture Sensor shall be thin plate, which is a good electrical conductor like, copper or aluminium, cut to about one square inch. Then, a small and smooth dent is made at the middle of the base (square plate), to hold a metallic ball, which shall be a good electrical conductor. Here, a ball (sphere shape) is made with soldering lead to have minimum electrical resistance and good electrical contact.
The square metallic base plate is surrounded by four thin strips, formed like walls, made of electrically insulated material like, hi-lam or foam sheet or card-board etc. These strips will hold the metallic ball within the square base plate. All the four corners of the walls are connected to small electrical conductors like, bare copper wire or copper strip or aluminium strip etc., just above the base plate. So. Whenever the metallic ball moved to a corner, the base plate and the conductor at the corner, shall have an electrical contact through the metallic ball, which acts as a switch. So, all the four corners behave like four switches, whenever the ball moves to the specific corners.
The making concept of the Hand Gesture Sensor with a metallic ball in the center and signal generation (working principle) with the metallic ball at various corners of the sensor are shown below. Two diodes are used to convert forward signal to generate both right and left signal simultaneously.
About Hand Gesture TX and RX:
The four signal outputs from the Hand Gesture Sensor are converted to three outputs and connected to four inputs of Encoder IC (HT12E), as shown in the above circuit diagram. Then the digital code is encoded by the Encoder IC, which outputs the code in serial format. Then the serial output of the encoder is transmitted by an RF transmitter
There is NO CHANGE in Receiver Board or Slim-Bot, w.r.t. Keypad Control system. Once the Hand Gesture Transmitter module is ready, then fix the Transmitter board behind your palm suitably. Now, switch ON the power supply to the Sensor Transmitter board and Slim-Bot for easy control of Slim-Bot using Hand Gesture Sensor. Now, move (or control) the Slim-Bot by tilting the hand forward, backward, left and right directions.
The complete Receiver circuit diagram is shown below.